Various types of lower back stretching devices are known in the prior art. The lower back muscles can be stretched by lifting the chest from a ground surface from a face down position or by bending down from the waist and returning to an upright position. Lower back exercise machines are provided which permit a seated user to push against a back rest thereof and move from an upright or forwardly included position into a rearwardly reclined position with both the seat and a foot plate in a stationary position during use. However, what is needed and provided by the present device is a lower back stretching device which is not a machine, but instead is a self-operated device which allows a user in a supine position with his buttocks supported by a cross-brace between a pair of side panels and with his knees resting atop a height-adjustable knee support bar to push and pull the handles of the device to rock the device back and forth on the convex bottom ends of the side panels in order to lift and stretch his lower back.